The stunning images produced so far by the James Webb Space Telescope (JWST) have captured the media.
They are easy to find online; just search for images from the James Webb Space Telescope. A very interesting novelty has just been released. It shows what looks more like a fingerprint in space. To see it, look at the link, (www.nasa.gov/feature/jpl/star-duo-forms-fingerprint-in-space-nasa-s-webb-finds)
It shows a pair of closely spaced stars surrounded by a set of at least 17 uniform, concentric, expanding ripples of dusty material. These dust ripples are because one of the stars is a Wolf Rayet star, with a mass about 30 times the mass of the sun.
The Wolf-Rayet stars, discovered in 1867 by Charles Wolf and Georges Rayet, astronomers at the Paris Observatory, are bright, massive stars that are nearing the end of their lives. These stars have masses 25 or more times the mass of the sun, but they shine 100,000 times to a million times brighter, so they use up their fuel at a prodigious rate. The sun is 4.5 billion years old and is still good for billions of years. Stars that become Wolf-Rayet stars last 10 to 30 million years before they run out of fuel, collapse, and explode.
When they start to run out of hydrogen, they start using heavier elements for energy, resulting in the waste of even heavier elements, such as iron. Normally, these accumulate in the core of stars and stay there until the star finally explodes, sending them out through the universe. However, the circulation of matter in Wolf-Rayet stars is so vigorous that heavy elements reach the surface, where they are ejected in the form of a particularly dense and fast version of the wind produced by our sun – the solar wind. . These heavy elements accumulate in the form of a cloud of dust surrounding the star.
However, in this case, the Wolf-Rayet story is a bit more interesting. The star in the JSWT image has a partner and the two stars orbit each other. Their paths around each other are quite elliptical, and each time the stars cross, their winds collide, creating another ring around the stars. This moves outwards and on the next close approach another ring is added. The result is a neat system of equally spaced rings that are clean and sharply defined. The ability of Wolf-Rayet stars to produce dust is easy to see in this image.
Bright stars that are retiring as Wolf-Rayet stars are not good places to look for life-bearing planets. A star living perhaps 30 million years will not allow its planets time to produce living beings. Moreover, such a vigorous wind from the star is likely to strip the atmospheres of all nearby planets. If anything survives this, they will be exterminated by the final explosion at the end of the star’s life.
This does not mean that these stars are not important for the development of life in our galaxy and apparently in other galaxies throughout the universe. Most of the other JWST images are beautiful combinations of stars and bright or dark dust clouds. This dust was produced by previous generations of massive, bright stars. At the beginning of the universe, there was only hydrogen, helium and possibly lithium. It is in the clouds of gas and dust that new stars and planets are born, and it is there that the ingredients are found to make living things.
These bright stars may never support life, but what they do makes life possible, and this JWST image of a pair of stars making dust ripples shows their part of the process very well and beautifully.
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Mercury, the planet closest to the sun, lies very low in the east before dawn. In the early evening, Jupiter is in the east and Saturn in the southeast. The Moon will reach first quarter on the 31st. There will be moonlight this Halloween.
Ken Tapping is an astronomer at the National Research Council Dominion Radio Astrophysical Observatory in Penticton.
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